Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true and idempotentHint=true, so safety is covered. The description adds substantial behavioral detail beyond annotations: inclusive UTC date semantics, a 400 error boundary at 400 days, row filtering to only days with envelope debit/refund/void_refund, and the required Authorization header. No annotation contradictions.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is front-loaded with the core purpose and then adds constraints, error behavior, row filtering, and auth requirements in four tight sentences. Every sentence adds material information without redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the output schema exists, return values need not be explained. The description covers the key callable constraints: date format, inclusivity, error threshold, row filtering semantics, and authentication, leaving no critical gaps for correct invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must carry the full burden for both parameters. It does so by specifying that start_date and end_date are inclusive UTC dates in YYYY-MM-DD format, plus the range constraint that triggers a 400 error.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific resource and scope: a daily credit-consumption report. It does not, however, distinguish this tool from sibling tools such as check_balance or get_pricing, so it falls short of a 5.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is implied by 'Daily credit-consumption report' and the date-range constraints, but the description never says when to use this tool versus alternatives like check_balance or get_pricing. It provides context but no explicit routing guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.